In recent years, a carbon dioxide (CO2) capture and storage technique has been attracting attention as an effective measure against the global warming problem. For example, a method of capturing carbon dioxide in an exhaust gas using an absorbing liquid has been examined for a combustion exhaust gas emitted from thermal power plants, a process exhaust gas emitted from ironworks, and the like. Examples of the absorbing liquid include an amine water solution.
Specifically, there is known a carbon dioxide capturing system which includes an absorption tower configured to bring an exhaust gas into contact with an absorbing liquid to cause the absorbing liquid to absorb carbon dioxide in the exhaust gas, and a regeneration tower configured to heat the absorbing liquid which has absorbed the carbon dioxide to release the carbon dioxide from the absorbing liquid. The absorbing liquid regenerated in the regeneration tower is supplied to the absorption tower and is reused. This system separates and captures the carbon dioxide in the exhaust gas by repeating the absorption of the carbon dioxide in the absorption tower and the release of the carbon dioxide in the regeneration tower.